Local residents were unable to call the emergency triple-0 service for several hours Thursday morning.

The Victorian Premier Ted Baillieu says the network breakdown could pose difficulties for emergency services in the region.

"We are ... concerned that those, particularly on a day like this, who receive pensions and receive funds through the internet may be disadvantaged and I know our team is working with the Commonwealth to alert them to those issues and to see what can be done in that regard," he said.

Police have set up temporary phone lines so residents can contact local police.

Telstra customers are able to reach emergency services by dialling triple-0 and police say stations in Warrnambool, Hamilton and Portland can be reached by temporary mobile phone numbers.

Satellite phones have been distributed to people with serious medical conditions.

Telstra's Bill Mundy says it could be days before all telephone lines are restored.

"From our perspective we're obviously continuing to work feverishly to bring in resources to get people connected," he said.

The roof of the building was badly damaged and firefighters say there is significant damage inside.

Telstra crews have spent the day assessing whether they will be able to restore power to the remaining exchange equipment.

The cause of the blaze is yet to be determined although police say it is not suspicious.